Über die Bindung von Aluminium aus Aluminiumchlorid‐Lösungen an Silicumdioxyd‐Oberflächen

Boehm, H. P.; Schneider, Manfred

doi:10.1002/zaac.19623160304

Cited by 26 publications

(3 citation statements)

References 18 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The presence of this signal is noted for all the samples analyzed, and the contribution of the species of Al V is increasing with the aluminum content. (iii) 51 ppm associated with tetrahedral Al (AlO 4 structural unit, Al IV ) corresponded to aluminum isomorphously substituting Si 4+ in silica frameworks or by grafted aluminum . The shift of the peak is observed from 55 ppm for Al20/SBA to 68 ppm for Al 2 O 3 , also the decreasing of the intensity is observed when increasing the aluminum content.…”

Section: Resultsmentioning

confidence: 91%

Emulsions Stabilized with Alumina-Functionalized Mesoporous Silica Particles

et al. 2020

View full text Add to dashboard Cite

Alumina-functionalized ordered mesoporous silica SBA-15 particles have been proposed to stabilize Pickering emulsions. Functionalization of SBA-15 particles have been performed by depositing alumina using a two-step synthesis (first, silica condensation, followed by alumina precipitation). Three different Al to Si ratios have been prepared. The calcined materials have been characterized by TEM, SEM, XRD, N2 physisorption, and zeta potential, in order to determine key physicochemical properties, and the alumina localization. The emulsifying and stabilizing properties of the calcined particles have been evaluated for water/toluene-based Pickering emulsions.

show abstract

Section: Resultsmentioning

confidence: 91%

Emulsions Stabilized with Alumina-Functionalized Mesoporous Silica Particles

et al. 2020

View full text Add to dashboard Cite

show abstract

“…Another indication is that ASA's acidity increases with the calcination temperature to be understood in terms of more extensive diffusion of Al into the silica network. 24 The acidic hydroxyl groups can be observed by IR spectroscopy after their selective H/D exchange under carefully chosen conditions. The differences in the overall Brønsted acidity of aluminosilicates are dominated by differences in the concentrations of these sites.…”

mentioning

confidence: 99%

Brønsted acid sites of zeolitic strength in amorphous silica-alumina

et al. 2010

View full text Add to dashboard Cite

show abstract

“…At pH values Weyand Siffert, 1961) between 5 and 10.5, at which aluminum is hardly soluble, the solubility of silica decreases drastically. Boehm and Schneider (1962) and Lieflander and Stober (1960) showed that amorphous silica is remarkably protected against dissolution by chemisorbed aluminum. For very high concentrations of magnesium the solubility of silica decreases even at pH values lower than 10.…”

Section: The Effect Of Ions Present In Solution On the Solubility Of mentioning

confidence: 99%

Colloid Geochemistry of Silica

Yariv

Cross

1979

Geochemistry of Colloid Systems

View full text Add to dashboard Cite

Silica, Si0 2 , is common in nature and occurs as seven distinct minerals, of which five show crystalline structures (quartz, tridimite, cristobalite, coesite, and stishovite) and two are amorphous (opal-A and lechatelierite). Lechatelierite is a silka glass and is very rare. Coesite and stishovite are also very rare and are found only in meteoritic craters, where they have been formed from quartz because of the high pressure resulting from the meteoritic impact. Opal is obtained by deposition from aqueous silica solutions at low temperatures. It is deposited by thermal waters associated with igneous activity and is also secreted by sponges, radiolaria, and diatoms. The most common form of silica is quartz.Amorphous silica is an important component of soils, coating particles of quartz, feldspar, and hornblende, as well as clay minerals (McKyes et aI., 1974). It also plays an important role as a cementation agent in many sediments. Monosilicic acid is an important constituent of natural aqueous solutions. In the pH range of normal natural water the monosilicic acid occurs predominantly as the uncharged Si(OH)4 species. However, suspended species of silicates are important and, according to Garrels and Mackenzie (1972), the dominant transfer of silicon in the sedimentary cycle occurs in the form of suspended quartz or suspended clay minerals. In their model the ratio of silica in the suspended flux to silica in the dissolved flux is about 4 to 1. From the Cambrian period (some 500-600 x 10 6 years ago) and in the present period most of the dissolved silica is removed from the oceans in the tests of organisms as opaline silica. Eventually, it is transformed to quartz as chert and/or overgrowth on detrital quartz grains or reincorporated into silicate minerals. According to Wise and Weaver (1974) chert formation is a "maturation" process, i.e., the aging of colloid silica system occurs as follows: The amorphous precipitate of biogenous silica is transformed into opal-CT, a poorly ordered crystalline form of silica that contains cristobalite and tridymite, and on further aging, into quartz.During the Precambrian period, prior to the advent of siliceous organisms, amorphous silica probably precipitated from marine waters by non-biogenous mechanisms. According to Oehler (1976) the diagenetic reactions culminating in biogenous and nonbiogenous chert formation may differ. Some nonbiogenous cherts were formed through an intermediate opal-CT stage and some crystallized directly from silica gel without the intervention of an intermediate crystalline phase such as opal-CT. The quartz crystallized primarily in the form of radially fibrous, chalcedonic spherulites, which later recrystallized to form anhedral grains, producing the interlocking mosaic texture typical of most cherts. The following diagenetic sequences were suggested by Oehler:S. Yariv et al., Geochemistry of Colloid Systems © Springer-Verlag Berlin Heidelberg 1979 248 Amorphous biogenous silica

show abstract

Über die Bindung von Aluminium aus Aluminiumchlorid‐Lösungen an Silicumdioxyd‐Oberflächen

Cited by 26 publications

References 18 publications

Emulsions Stabilized with Alumina-Functionalized Mesoporous Silica Particles

Emulsions Stabilized with Alumina-Functionalized Mesoporous Silica Particles

Brønsted acid sites of zeolitic strength in amorphous silica-alumina

Colloid Geochemistry of Silica

Contact Info

Product

Resources

About